Battery-Less Biopotential Recording IC With RF Power Harvesting
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Solution Overview
Problem
Implantable cardiac devices, such as pacemakers, face challenges due to the need for batteries, which make them bulky and prone to issues like catastrophic failures and clogged arteries, while energy harvesting methods like piezoelectric and RF energy harvesting face limitations in power generation and antenna size within the human body.
Innovation Solution
A wirelessly powered, battery-less biopotential recording IC system utilizing on-chip antennas and separate low dropout voltage regulators for precise power delivery, incorporating a power harvesting circuit, clock recovery circuit, and analog-to-digital converter to record and transmit cardiac signals, with a power management unit controlling energy distribution and transmitter operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If batteries are used in implantable cardiac devices, then the devices can provide continuous power for pacemaker operation, but the devices become bulky and are prone to catastrophic failures and clogged arteries
Solution Approach 1:
The patent extracts and eliminates the battery component from the implantable device entirely. The system uses wireless power transmission to deliver energy externally, allowing the implantable device to be battery-less and significantly smaller while maintaining continuous operational capability through received RF power signals.
Solution Approach 2:
The patent introduces an external power transmission system as an intermediary between the power source and the implantable device. The external transmitter communicates with and powers the implantable device wirelessly through RF signals, eliminating the need for internal batteries while providing continuous power supply.
2Use of energy by moving object
If piezoelectric energy harvesting is used, then the device can be battery-less, but the power generation capability is insufficient within the human body
Solution Approach 1:
The patent employs a dual energy harvesting approach that combines both piezoelectric energy harvesting from mechanical body movements and RF energy harvesting from external wireless power transmission. This multi-functional energy acquisition system overcomes the insufficient power output of piezoelectric alone by supplementing it with RF power, enabling reliable battery-less operation.
3Volume of moving object
If RF energy harvesting is used with on-chip antennas, then the device size can be reduced, but the antenna size is constrained within the human body
Solution Approach 1:
The patent divides the power transmission system into two separate components: a large external transmitter that can generate sufficient RF power with appropriate antenna size, and a small implantable receiver with a compact on-chip antenna. This segmentation allows the external device to compensate for the limited antenna size in the implantable device, maintaining energy harvesting efficiency while minimizing implantable device volume.
4Measurement precision
If separate low dropout voltage regulators are used for precise power delivery, then power distribution accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements separate low dropout voltage regulators tailored to specific functional blocks within the implantable device. Each regulator is optimized for its local power requirements, providing precise power delivery to sensitive components like the ADC and processing circuits. This localized power regulation approach improves overall power distribution accuracy while keeping each regulator simple and focused on specific functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables fully battery-less operation for implantable leadless cardiac monitoring, reducing device size and eliminating battery-related risks, while achieving efficient energy harvesting and accurate cardiac signal recording and transmission.
Implementation Method 1
a power harvesting circuit configured to harvest energy from the first RF signal
Implementation Method 2
a wireless receiver configured to receive a first radio frequency (RF) signal. The sensor device includes one or more wireless transmitters, wherein at least one wireless transmitter is configured to transmit a second RF signal
Data Source
AI summary
Systems and methods for biopotential recording integrated circuits are illustrated. One embodiment includes a wireless receiver configured to receive a first radio frequency (RF) signal; one or more wireless transmitters; and a processing circuitry, comprising: a power harvesting circuit configured to harvest energy from the first RF signal; a clock recovery circuit configured to extract a clock signal from the first RF signal; at least one sensing electrode configured to record an electric signal as at least one of a voltage, current, and electric charge; and an analog-to-digital converter (ADC) communicatively coupled to the clock recovery circuit.